VHF Marine Radio

VISA uses channel 78A for all regatta and general VHF radio communications.

VHF Channels and Use

Frequencies within VHF marine band are divided into "channels" for convenience and these channels are further reserved for specific purposes. The chart below summarizes the use for each channel within the VHF marine band:

Distress, Safety, and Hailing

16

Use this channel to get the attention of another station (calling) or in emergencies (distress and safety).

Intership Safety

6

Use this channel for ship-to-ship safety messages and for search and rescue messages to ships and aircraft of the Coast Guard.

Coast Guard Liason

22

Use this channel to talk to the Coast Guard (but first make contact on Channel 16).

Non-Commercial

96, 679,68, 69, 718, 72, 78, 794, 804

Working channels for voluntary boats. Messages must be about the needs of the ship. Typical uses include fishing reports, rendezvous,scheduling repairs and berthing information. Use Channels 67 and 72 only for ship-to-ship messages.

Commercial

15, 7, 8, 9, 10, 11, 18, 19, 635, 677, 79, 80, 88A1

Working channels for working ships only. Messages must be about business or the needs of the ship. Use channels 8, 67, 72 and 88A only for ship-to-ship messages.

Public Correspondence (Marine Operator)

24, 25, 26, 27, 28, 84, 85, 86

Use these channels to call the marine operator at a public coast station. By contacting a public coast station, you can make and receive calls from telephones on shore. Except for distress calls, public coast stations usually charge for this service.

Port Operations

15, 53, 12, 14, 20, 635, 65, 66, 73, 74, 7510,7610, 77

These channels are used in directing the movement of ships in or near ports, locks or waterways. Messages must be about the operational handling movement and safety of ships. In certain major ports, Channels 11,12 and are not available for general port operations messages. Use channel 20 only for ship-to-coast messages. Channel 77 is limited to intership communications to and from pilots.

Navigational (Also known as the bridge-to-bridge channel)

13,67

This channel is available to all ships. Messages must be about ship navigation, for example, passing or meeting other ships. You must keep your messages short. Your power output must not be more than one watt. This is also the main working channel at most locks and drawbridges.

Maritime Control

17

This channel may be used to talk to ships and coast stations operated by state or local governments. Messages must pertain to regulation and control, boating activities, or assistance to ships.

Digital Selective Calling

70

Use this channel for distress and safety calling and for general purpose calling using only digital selective calling techniques.

Background

VHF, which stands for Very High Frequency, refers to a frequency range used for both marine and aviation radio traffic, among others. VHF radio encompasses the frequency range from 30 to 300 megahertz with 118 to 137 megahertz reserved for civil aviation and 156 to 162.025 megahertz reserved for marine use.

UHF, or Ultra High Frequency, is the more common standard frequency range used for radio traffic on land. UHF represents the frequency range between 300 megahertz and 3 gigahertz.

UHF radio waves are capable of penetrating buildings and other obstacles, while carrying considerable data. By contrast, VHF radio waves, with longer wavelenghts, are stictly line of sight but are capable of traveling over twice the distance of UHF. For this reason, VHF is the preferred frequency range for communications over open water and air.

Antenna Height, Signal Strength, and Distance

Since VHF is a limited to line-of-sight applications, the curvature of the Earth is a limiting factor on VHF signal propagation. For a man standing on level ground at sea level, the horizon is approximately 3 statute miles away. For this reason, the signal range for most handheld VHF radios broadcasting with a transmission power of between 3-6 watts, is typically quoted in the 5 mile range.

However, if the VHF radio antenna is placed at the top of a sailboat's mast, the line-of-sight distance to the hoizon can be increased to over 20 miles. When a sailboat is equipped with a fixed mount VHF radio broadcasting with 25 watts, the effective range of the transmission can exceed 20 miles. Fixed mount VHF radios offer greater transmission power than handheld units (25 watts versus 3-6 watts), but the biggest factor in signal propagation is the height of the antenna.